CFRD incidence, mortality rates narrowed

Cystic fibrosis-related diabetes is present in 2% of children, 19% of adolescents and 45% to 50% of adults aged older than 30 years, according to a review of data from 1992 to 2008.

The review revealed that previously noted differences in cystic fibrosis-related diabetes between sexes and gaps in mortality have disappeared and considerably narrowed, with the exception of a higher prevalence in women aged 30 to 39 years.

“Diabetes is exceptionally common in cystic fibrosis, especially as cystic fibrosis patients get older,” Antoinette Moran, MD,told Endocrine Today.

“In the past, the added diagnosis of diabetes has meant a patient (especially a woman) with cystic fibrosis is at increased risk for early death — this is no longer the case,” she said. “We believe the difference is that we are now screening effectively so that we diagnose early and we are treating it aggressively.”

Moran and colleagues at the University of Minnesota examined current trends in the incidence, prevalence and mortality related to cystic fibrosis-related diabetes using a comprehensive clinical database. The review included 872 patients with cystic fibrosis followed at the University of Minnesota during 1992 to 1997, 1998 to 2002 and 2003 to 2008.

Current trends

During 15 years, cystic fibrosis-related diabetes mortality rates decreased by more than 50% in women, from 6.9 deaths per 100 patient-years in 1992 to 1997 to 3.2 deaths per 100 patient-years in 2003 to 2008. Rates also decreased in men — 6.5 deaths per 100 patient-years in 1992 to 1997 to 3.8 deaths per 100 patient-years in 2003 to 2008.

The overall incidence of cystic fibrosis-related diabetes was 2.7 cases per 100 patient-years, with the exception of women aged 30 to 39 years in whom the incidence more than doubled.

Previously, diabetes was diagnosed as a perimorbid event in nearly 20% of patients with cystic fibrosis. During 2003 to 2008, only two of 61 patients diagnosed with diabetes died.

Cystic fibrosis-related diabetes without fasting hyperglycemia predominated in younger patients; however, the presence of fasting hyperglycemia rose with age.

Still, lung function is worse in patients with cystic fibrosis-related diabetes compared with patients without diabetes. Nutritional and pulmonary statuses were similar between patients with and without fasting hyperglycemia.

The data are “encouraging” because “diabetes is an expected condition as individuals with cystic fibrosis grow older,” Moran said during the interview.

The researchers attributed several reasons to the improved incidence, prevalence and mortality rates related to cystic fibrosis-related diabetes, including more aggressive treatment and early diagnosis.

Better antibiotics, digestive enzymes and respiratory therapies may have also contributed to the changes. “However, these therapies affect all people with cystic fibrosis and it is those with diabetes who have shown the greatest improvement,” Moran said.

Moran A. Diabetes Care. 2009;32:1626-1631.